This invention relates to a quick connection-release coupling used as a coupling for connecting a fluid transferring hose or the like and, more particularly, to a quick connection-release coupling capable of being used in a pressure range from low pressure to high pressure.
In the prior art, there is known union joints used as couplings for connecting a fluid transferring hose. In general, the union joint employs a ball-locking system for connecting a female coupling part with a male coupling part. Since the ball used produces a point contact in regard to the female coupling part and the male coupling part, a special processing such as a heat treatment and the like is applied to increase the strength of the ball. Due to this fact, there is a problem that the union joint is expensive. Additionally, since a tool such as a wrench must be used to connect and release the joint, its connection and release operation is troublesome. As a result, there is another problem that it takes much time to perform maintenance work.
On the other hand, there are well known quick connection-release couplings used as couplings for connecting a fluid transferring hose, employing a C-shaped spring ring system shown in FIG. 12. The coupling includes a female coupling part having a cylindrical adapter 21 and a cap 22 attached thereto, a slit 23 being formed in the inner surface of the cap 22, and a C-shaped spring ring 24 which is resiliently expandable and retractable being located in the slit 23. The male coupling part of the quick connection-release coupling which is inserted into the female coupling part has a cylindrical nipple 25, an annular engagement portion 26 for engaging with the C-shaped spring ring 24 being protruding on the outer circumferential surface of the cylindrical nipple 25 and extending along the circumferential direction. A releasing jig 28 having a dust-proof cap 27 fixed thereto is slidably attached to the outer circumferential surface of the nipple 25. Reference numeral 29 denotes an O-ring for sealing, and reference numeral 30 denotes a socket fixed to the nipple 25.
When attaching the nipple 25 to the adapter 21, the nipple 25 is inserted into the adapter 21 and the C-shaped spring ring 24 is engaged with the engaging portion 26, whereby the nipple 25 is locked in the adapter 21 (the state shown in FIG. 12). When releasing the nipple 25 from the adapter 21, the releasing jig 28 is moved forward in the arrow direction and the front end portion of the releasing jig 28 inserted through a clearance between the cap 22 and the nipple 25 is pushed against the C-shaped spring ring 24. The further pushing movement of the releasing jig 28 forces the C-shaped spring ring 24 pushed by the releasing jig 28 radially expand gradually and ride over the top of the engaging portion 26, thereby releasing the engaged state between the C-shaped spring ring 24 and the engaging portion 26.
A quick connection-release coupling of the type described above has an advantage that its connection-release operation can be easily performed and a maintenance work time can be shortened because an operator can manually connect and release it without using any tool. The C-shaped spring ring 24 is line contacted with the adapter 21 and the nipple 25, resulting in that it can be used without performing any special processing such as heat treatment, etc. In addition, since the quick connection-release coupling can have less component parts than the union joint, if compared, it is possible to attain a low cost.
However, since the connection-release work is carried out manually, it is not possible to use either a C-shaped spring ring having a wire diameter exceeding 1.0 mm or a C-shaped spring ring made of high-strength material having a high elastic modulus of 180,000N/mm2 such as stainless steel material, which particularly makes the releasing operation difficult. Accordingly, although the aforesaid quick connection-release coupling has the superior advantages as described above, it has a problem that it is exclusively used for low-pressure fluid and it cannot be used for high-pressure fluid.
It is an object of the present invention to provide a quick connection-release coupling capable of being used in a range from low pressure to high pressure without reducing the superior advantages of the aforesaid quick connection-release coupling.
To achieve the above object, the present invention provides a quick connection-release coupling comprising a female coupling part having a cylindrical adapter, along an inner circumferential surface of which a resiliently expandable and retractable C-shaped spring ring is arranged, and a male coupling part having a cylindrical nipple with an engaging portion protruded on an outer circumferential surface thereof, the engaging portion being capable of being engaged with and disengaged from the C-shaped spring ring, the nipple being connectable to the adapter when pushed into the adapter so as to engage the C-shaped spring ring with the engaging portion, and being detachable from the adapter when the engaged state between the engaging portion and C-shaped spring ring is released by expanding the C-shaped spring by pushing the C-shaped spring, characterized in that a cylindrical releasing jig being movable forward and backward against the engaging portion is threadably arranged on the outer circumferential surface of the nipple, and the engaged state between the engaging portion and C-shaped spring ring can be released when the C-shaped spring ring is expanded by moving the releasing jig forward and by pushing the C-shaped spring ring in the separating operation of the nipple from the adapter.
In accordance with the quick connection-release coupling of the present invention, even if a spring material having a high elastic modulus and a high strength or a thick wire material greater than 1.0 mm in wire diameter, used for high pressure fluid, is employed, a manually turning operation of the releasing jig by an operator enables the engaged state between the engaging portion and the C-shaped spring ring to be easily released because of releasing it using an advancing force by screwing of the releasing jig, thereby allowing the nipple to be detached from the adapter. Accordingly, one coupling can be used in a wide pressure range from low pressure to high pressure.
Since the releasing jig is constructed such that it is threadably fitted, the superior advantages such as a reduction in maintenance operation time and low cost found in the prior art quick connection-release coupling are not deteriorated.